Back in the ’70s, almost a hundred reporters around the country – Washington Post bureau chiefs, rovers, freelancers and me, their desk-bound editor – were trying to get our arms around how North America worked, really. Not how it should work. But how it did work. State by province by region, we started drawing the fault lines on maps, and sometimes on cocktail napkins. Forget those nice neat rectangles in the middle of the U.S. Let’s be real: The mountains of western Colorado are totally alien from the wheat fields of eastern Colorado. And Miami is part not of Florida, but its own watery Caribbean realm. And what a terrible idea is “California.” It behaves as if it covers three warring civilizations.

A map based on culture and values does not reflect the perversely drawn state and national boundaries.

The result was my 1981 book, “The Nine Nations of North America.” The reader reaction was astonishing. This map – drawn to anticipate the news – revealed something much deeper. It turned out to be a map of culture and values, which have nothing to do with our perversely drawn state and national boundaries. That’s why the “nine nations” idea became a cult item among marketers, broadcasters, political operatives and even carmakers – who have to understand who we are, how we got that way and what makes us tick. To this day, other authors adopt the Nine Nations method to explain China, Europe, Mexico, the former Soviet Union and even the Middle East.

More than three decades after publication, two things amaze me: how little the boundaries have changed and how much chatter this idea is getting recently. Much of the online discussion in the last few years has been spurred by dismay over American national gridlock and the “nine nations” divisions that fuel it. The gridlock has grown, but the divisions are not new.

Despite the turbulence in technology, finance, energy, population, mobility and polity, the boundaries still make sense as drawn in 1981 – even where events have gone exactly opposite my expectations. (For example, North Carolina is even more “Dixie” today than when I wrote.) Check out the last few presidential election results at the U.S. county level, and these boundaries still pop right out at you. In Canada, it’s even more striking.

One explanation for this endurance may be that those boundaries were observed by a network of dedicated amateur anthropologists all over the continent that, by pre-Internet standards, was vast. The network worked!

But what seems to really endure is culture and values. They are slow to change, and far more so than I originally guessed. The layers of unifying flavor and substance that define these nations still explain the major storms through which our public affairs pass. And “Nine Nations” is also a map of power, money and influence, the patterns of which have only deepened.

Travel is still the great North American pastime because of our enduring diversity. Out of a sense of adventure, we still look forward to picking up our belongings and taking a new job in a different place. Trying on different values, different senses of the pace at which life should be lived, different attitudes about art, food and ethnic origin, a different relationship to nature. Yet every North American also knows a place where, on your way back from your wanderings, surroundings stop feeling threatening, confusing or strange.

Ultimately, that is the reason we are nine nations. When you’re from one, and you’re in it, you know you’re home.